bulk rename

It's very simple command, but I never used before [I was going to write a script for this req. :)]

[mandy@mandy mpix]$ ls *20121031000012*
mp1_20121031000012.txt  mp2_20121031000012.txt  mp3_20121031000012.txt

[mandy@mandy mpix]$ rename "20121031000012" "20121031000013" *20121031000012.txt

[mandy@mandy mpix]$ ls *20121031000013*
mp1_20121031000013.txt  mp2_20121031000013.txt  mp3_20121031000013.txt